Structure, function and evolution of seryl-tRNA synthetases: implications for the evolution of aminoacyl-tRNA synthetases and the genetic code

J Mol Evol. 1995 May;40(5):519-30. doi: 10.1007/BF00166620.


Two aspects of the evolution of aminoacyl-tRNA synthetases are discussed. Firstly, using recent crystal structure information on seryl-tRNA synthetase and its substrate complexes, the coevolution of the mode of recognition between seryl-tRNA synthetase and tRNA(ser) in different organisms is reviewed. Secondly, using sequence alignments and phylogenetic trees, the early evolution of class 2 aminoacyl-tRNA synthetases is traced. Arguments are presented to suggest that synthetases are not the oldest of protein enzymes, but survived as RNA enzymes during the early period of the evolution of protein catalysts. In this view, the relatedness of the current synthetases, as evidenced by the division into two classes with their associated subclasses, reflects the replacement of RNA synthetases by protein synthetases. This process would have been triggered by the acquisition of tRNA 3' end charging activity by early proteins capable of activating small molecules (e.g., amino acids) with ATP. If these arguments are correct, the genetic code was essentially frozen before the protein synthetases that we know today came into existence.

Publication types

  • Comparative Study
  • Review

MeSH terms

  • Acylation
  • Amino Acid Sequence
  • Amino Acyl-tRNA Synthetases / chemistry
  • Amino Acyl-tRNA Synthetases / classification
  • Amino Acyl-tRNA Synthetases / genetics
  • Animal Population Groups / genetics
  • Animal Population Groups / metabolism
  • Animals
  • Bacterial Proteins / chemistry
  • Bacterial Proteins / genetics
  • Catalysis
  • Escherichia coli / enzymology
  • Escherichia coli / genetics
  • Fungal Proteins / chemistry
  • Fungal Proteins / metabolism
  • Genetic Code*
  • Humans
  • Models, Molecular
  • Molecular Sequence Data
  • Phylogeny*
  • Protein Binding
  • Protein Conformation
  • RNA, Bacterial / metabolism
  • RNA, Fungal / metabolism
  • RNA, Transfer, Ser / metabolism*
  • Saccharomyces cerevisiae / enzymology
  • Saccharomyces cerevisiae / genetics
  • Sequence Alignment
  • Sequence Homology, Amino Acid
  • Serine-tRNA Ligase / chemistry*
  • Serine-tRNA Ligase / genetics
  • Species Specificity
  • Thermus / enzymology


  • Bacterial Proteins
  • Fungal Proteins
  • RNA, Bacterial
  • RNA, Fungal
  • RNA, Transfer, Ser
  • Amino Acyl-tRNA Synthetases
  • Serine-tRNA Ligase

Associated data

  • GENBANK/P09156
  • GENBANK/P26636
  • GENBANK/P26638
  • GENBANK/P34945
  • GENBANK/T03561
  • GENBANK/X75627